Black Swan (2003)

Sam Baker is on the case to solve a horrific murder of a young woman, but along the way he discovers that there is more going on in his own little world then meets the eye. Strange visions of the past appear to him, and finally he discovers that to catch the killer he must become the victim, literally. Questions soon arise about Sam's sanity, is he really a detective on this case, is he the victim, is he the killer... or worse, is this all in his mind.